[This note covers all of the notebooks in Group 2: Storage Battery Endurance Tests.]

The 399 books in this group cover the period April 1903-December 1914, although there are several books with entries from as late as 1917. They were used by Edison employees, including Alvin D. Caskey, Ignacy Goldstein, Walter E. Holland, George H. Hooper, Jr., and Joseph W. Valentine, to record endurance and efficiency tests performed on storage batteries or to record testing conditions. There are many entries initialed by Edison, as well as occasional marginal notations by him, which indicate his attention to their work. Among the cells tested are experimental and production versions of Edison types A4, A6, A8, B2, B4, and E18, along with several competitors' cells. The tests pertain to variations in cell performance under different charge and discharge conditions and according to differing compositions or constructions of cells and cell components. Labels on the front covers of some of the books contain notes by Edison regarding the importance of the data contained therein. The notebooks are arranged in four subgroups: (1) General Endurance Tests (304 books); (2) Tube Tests (58 books); (3) TAE Reports (30 books); and (4) Goldstein Nickel Hydrate Books (7 books).